CallbackLED.ino

/*
  Callback LED

  This example creates a BLE peripheral with service that contains a
  characteristic to control an LED. The callback features of the
  library are used.

  The circuit:
  - STEVAL-MKSBOX1V1, B-L475E-IOT01A1, or a Nucleo board plus the X-NUCLEO-IDB05A1 or the X-NUCLEO-BNRG2A1

  You can use a generic BLE central app, like LightBlue (iOS and Android) or
  nRF Connect (Android), to interact with the services and characteristics
  created in this sketch.

  This example code is in the public domain.
*/

#include <STM32duinoBLE.h>

#if defined(ARDUINO_STEVAL_MKSBOX1V1)
/* STEVAL-MKSBOX1V1 */
SPIClass SpiHCI(PC3, PD3, PD1);
HCISpiTransportClass HCISpiTransport(SpiHCI, SPBTLE_1S, PD0, PD4, PA8, 1000000, SPI_MODE1);
BLELocalDevice BLE(&HCISpiTransport);
#elif defined(ARDUINO_DISCO_L475VG_IOT)
/* B-L475E-IOT01A1 */
SPIClass SpiHCI(PC12, PC11, PC10);
HCISpiTransportClass HCISpiTransport(SpiHCI, SPBTLE_RF, PD13, PE6, PA8, 8000000, SPI_MODE0);
BLELocalDevice BLE(&HCISpiTransport);
#else
/* Shield IDB05A1 with SPI clock on D3 */
SPIClass SpiHCI(D11, D12, D3);
HCISpiTransportClass HCISpiTransport(SpiHCI, SPBTLE_RF, A1, A0, D7, 8000000, SPI_MODE0);
BLELocalDevice BLE(&HCISpiTransport);
/* Shield IDB05A1 with SPI clock on D13 */
/*SPIClass SpiHCI(D11, D12, D13);
HCISpiTransportClass HCISpiTransport(SpiHCI, SPBTLE_RF, A1, A0, D7, 8000000, SPI_MODE0);
BLELocalDevice BLE(&HCISpiTransport); */
/* Shield BNRG2A1 with SPI clock on D3 */
/*#define SpiHCI SPI
HCISpiTransportClass HCISpiTransport(SpiHCI, BLUENRG_M2SP, A1, A0, D7, 1000000, SPI_MODE1);
BLELocalDevice BLE(&HCISpiTransport); */
/* Shield BNRG2A1 with SPI clock on D13 */
/*#define SpiHCI SPI
HCISpiTransportClass HCISpiTransport(SpiHCI, BLUENRG_M2SP, A1, A0, D7, 1000000, SPI_MODE1);
BLELocalDevice BLE(&HCISpiTransport); */
#endif

BLEService ledService("19B10000-E8F2-537E-4F6C-D104768A1214"); // create service

// create switch characteristic and allow remote device to read and write
BLEByteCharacteristic switchCharacteristic("19B10001-E8F2-537E-4F6C-D104768A1214", BLERead | BLEWrite);

const int ledPin = LED_BUILTIN; // pin to use for the LED

void setup() {
  Serial.begin(115200);
  while (!Serial);
  
  pinMode(ledPin, OUTPUT); // use the LED pin as an output

  // begin initialization
  if (!BLE.begin()) {
    Serial.println("starting BLE failed!");

    while (1);
  }

  // set the local name peripheral advertises
  BLE.setLocalName("LEDCallback");
  // set the UUID for the service this peripheral advertises
  BLE.setAdvertisedService(ledService);

  // add the characteristic to the service
  ledService.addCharacteristic(switchCharacteristic);

  // add service
  BLE.addService(ledService);

  // assign event handlers for connected, disconnected to peripheral
  BLE.setEventHandler(BLEConnected, blePeripheralConnectHandler);
  BLE.setEventHandler(BLEDisconnected, blePeripheralDisconnectHandler);

  // assign event handlers for characteristic
  switchCharacteristic.setEventHandler(BLEWritten, switchCharacteristicWritten);
  // set an initial value for the characteristic
  switchCharacteristic.setValue(0);

  // start advertising
  BLE.advertise();

  Serial.println(("Bluetooth device active, waiting for connections..."));
}

void loop() {
  // poll for BLE events
  BLE.poll();
}

void blePeripheralConnectHandler(BLEDevice central) {
  // central connected event handler
  Serial.print("Connected event, central: ");
  Serial.println(central.address());
}

void blePeripheralDisconnectHandler(BLEDevice central) {
  // central disconnected event handler
  Serial.print("Disconnected event, central: ");
  Serial.println(central.address());
}

void switchCharacteristicWritten(BLEDevice central, BLECharacteristic characteristic) {
  // central wrote new value to characteristic, update LED
  Serial.print("Characteristic event, written: ");

  if (switchCharacteristic.value()) {
    Serial.println("LED on");
    digitalWrite(ledPin, HIGH);
  } else {
    Serial.println("LED off");
    digitalWrite(ledPin, LOW);
  }
}